Large scale survey of yeasts in frozen concentrated orange juice (FCOJ): Occurrence, diversity, and resistance to peracetic acid

This study aimed to evaluate the occurrence and diversity of yeasts in frozen concentrated orange juice (FCOJ) and assess the resistance of yeasts to peracetic acid. One thousand five hundred (n = 1500) samples of frozen concentrated orange juice (FCOJ) were analyzed, and 280 yeast strains were isolated and identified. Candida represented 37% of all isolates, and the main species identified were Candida pseudointermedia and C. orthopsilosis. Other yeasts identified were Starmerella, Wickerhamiella, Wickerhamiella, Clavispora, Kodamaea, Meyerozyma, Rhodotorula, Trichosporon, Wickerhamomyces, Kluyveromyces, Hanseniaspora, Saccharomyces, Torulaspora, and Zygosaccharomyces. The exogenous origin of the contamination in FCOJ samples analyzed was shown by the high diversity, corroborated by the Simpson (D) and Shannon (H') indices. From a total of 227 yeasts strains tested, more than 20% were able to withstand peracetic acid concentrations >200 ppm, with emphasis on W. anomalus (300 ppm), W. sergipensis (350 ppm), C. rugopelliculosa (350 ppm), K. marxianus (450 ppm), C. parapsilosis (500 ppm), C. pseudointermedia (500 ppm), W. sorbosivorans (500 ppm), C. boleticola (600 ppm), S. cerevisiae (700 ppm) and C. orthopsilosis (750 ppm). This study adds novel data regarding the occurrence and diversity of yeasts present in FCOJ and their resistance to a chemical compound commonly employed in the sanitization of processing and distribution premises and vehicles. These findings are essential to support the development of measures for proper mitigation of contamination of orange juice towards reducing the risks of spoilage by yeasts during FCOJ transportation/storage or when FCOJ is used as an ingredient.